useDEMGravitationalModel

s1tbx
#1

Hi,
in the file s1tbx.config file I see the card useDEMGravitationalModel
The card is set to true
My question is: is this card effectively used in the s1tbx work flow?
I don’t see any other occurrence of this string in the s1tbx source code
Thanks for any suggestion
Davide

#2

The DEMGravitationalModel for SRTM should always be used. This was just here for debugging purposes and in fact should be in the snap.properties if it is to be used at all.

#3

Dear Iveci,
thanks for your reply. So, do you confirm that orthometric to ellipsoidic height conversion is applied to SRTM auxiliary DEMs during Back-Geocoding and Topographic Phase Removal?

#4

Dear Iveci,
thanks for your reply. So, do you confirm that orthometric to ellipsoidic
height conversion is applied to SRTM auxiliary DEMs during Back-Geocoding
and Topographic Phase Removal?

#5

No, the other way around. The SRTM references the ellipsoid and its made to reference the geoid to include the height differences caused by the Earths gravity.

geoid2_lg.gif1024×780 44.2 KB

#6

I need be sure about one information. I created DEM using pair of SLC products in S1TBX. Output heights are orthometric or elipsoid? There is no posibility to convert elevation band from one height system to another? Thanks in advance for your answer.

#7

How i can apply geoid height on my generated DEM.?

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#8

@lveci Question about current state of s1tbx.config parameter “useDEMGravitationalModel”: Is this still used for version 7 and 8? “Apply Earth Gravitational Model” is now an option on some modules when using External DEMs. However, this is not an option for Back Geocoding.
Should the External DEMs for Back Geocoding be in elipsoidal or geoidal height, or it does not make any difference?

@sumiya I have used StereoPipeline to convert DEM vertical reference. Note: Use “–tif-compress none” for DEMs used with SNAP. Compression of DEMs still causes unusual errors in rev 8.